Related Experiment Video
Updated: Aug 2, 2025

Phase Behavior of Charged Vesicles Under Symmetric and Asymmetric Solution Conditions Monitored with Fluorescence Microscopy
Published on: October 24, 2017
Unusual phosphatidylcholine lipid phase behavior in the ionic liquid ethylammonium nitrate
Livia Salvati Manni1, Caitlin Davies2, Kathleen Wood3
1School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia; School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, NSW, Australia.
Hypothesis:
The forces that govern lipid self-assembly ionic liquids are similar to water, but their different balance can result in unexpected behaviour.
Experiments:
The self-assembly behaviour and phase equilibria of two phospholipids, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in the most common protic ionic liquid, ethylammonium nitrate (EAN) have been investigated as function of composition and temperature by small- and wide-angle X-ray scattering (SAXS/WAXS) and small-angle neutron scattering (SANS).
Findings:
Both lipids form unusual self-assembly structures and show complex and unexpected phase behaviour unlike that seen in water; DSPC undergoes a gel Lβ to crystalline Lc phase transition on warming, while POPC forms worm-like micelles L1 upon dilution. This surprising phase behaviour is attributed to the large size of the EAN ions that solvate the lipid headgroup compared to water changing amphiphile packing. Weaker H-bonding between EAN and lipid headgroups also contributes. These results provide new insight for the design of lipid based nanostructured materials in ionic liquids with atypical properties.
Related Concept Videos
Synthesis of Phosphatidylcholine in the ER Membrane
The major components of all eukaryotic cell...
Asymmetric Lipid Bilayer
Membrane Fluidity
What are Lipids?

